SFTP Tab (Login Dialog)

Protocol Options

Use SFTP server to specify path to
SFTP server binary.
Keep value Default to use the default
SFTP server.
Usually there will not be more
SFTP servers to
choose from. However you may find the option useful to change
the way the SFTP
server is launched.
Particularly you may want to change user (known as su)
(see note 1).

Use Preferred SFTP protocol version to
configure maximal version of SFTP protocol that
WinSCP will attempt to use. WinSCP will seamlessly downgrade to any lower version that the server
supports. The only reason, that you may want to change the option for, is bug either in
SFTP server or WinSCP itself specific to particular
version of the protocol.

Detection of Known Bugs in SFTP Servers

The box allows you to configure the bugs WinSCP should expect to see in the
SFTP server.

Each bug can be configured in three states. With Off WinSCP will assume that the server does
not have the bug. With On WinSCP will assume that the server does have the bug. With
Auto (default) WinSCP will try to guess whether or not the server has the bug. The guessing
is mostly based on software version string of the SSH server,
as most current SFTP servers does announce their
software version strings.

WinSCP can work around the bugs of major SFTP
servers only. There is many more known bugs in SFTP
server implementations. Read more about interoperability with
SFTP servers.

Reverses Order of Symlink Command Arguments

The SFTP command to create a symbolic link (symlink) has two
arguments: the path the symbolic link should point to and the path of the symlink itself. Some servers
incorrectly expects the arguments in reversed order.

If the bug is detected, WinSCP will reverse the order of the arguments too.

The bug is known on SFTP servers shipped with all
versions of OpenSSH (bug
#861).

Misinterprets File Timestamps Prior to 1970

While specification for SFTP protocol version 3
and older defines file timestamp to be unsigned 32-bit number representing number of seconds from
Jan 1, 1970 in UTC, at least OpenSSH interprets
it as signed number. The result is that files on the server with timestamps before 1970 will be interpreted
by WinSCP as times after 2038. As it is probably quite common bug, it is currently considered to apply
for all servers. Set the option to Off if it does not for your server.

This is SFTP-3 and older specific bug.
SFTP-4 introduced signed 64-bit timestamps.